This invention relates in general to a sterile package water detection system.
Sterile packages, such as blister packages or surgical kits, generally include a plastic shell having a barrier lid sealed thereto by means of a heat sealable coating on the reverse side of the lid. The package contents and interior are sterilized by passing a gas, such as ethylene oxide, through the pores of the lid and its coating. The pores are small enough to resist bacterial penetration, but may pass moisture. If even a small quantity of water should pass the barrier lid, the sterile condition may be lost.
One problem therefore is to provide an indication that water penetration has occurred.
Another problem is that after a package has been penetrated by water and dried, a memory or record of the prior wetting must be retained to indicate the possible contamination. Still another problem is that such moisture indicating system must be economical and compatible with presently used materials and practices.
Prior art moisture or water indicators using color-change compositions are sometimes ineffective because the operator must be aware of what color designates a moisture condition. Also, the color change may be subtle and not easily differentiated. Further, the operator might be color blind to the color change. Additionally, most moisture or water detection papers do not leave a permanent record. For example, commonly used cobalt chloride detection paper will turn from blue (dry condition) to pink (wet condition). However, upon subsequent drying the paper will return to blue without leaving a record of being wetted.
Accordingly, one object of the present invention is to provide a novel water detection system for a sterile package.
Another object of the present invention is to provide a water detection system for a sterile package which indicates the leak occurrence, after the water has dried.
Still another object of the present invention is to provide a water detection system for a sterile package which is economical and which would readily and immediately indicate a moisture condition.
Other objects and advantages of the invention will become apparent as the description proceeds.